I'll repay the same courtesy: Your argument is predicted and refuted by your sibling thread of twenty minutes ago. https://news.ycombinator.com/item?id=9501084
Microaggression is a term of jargon, as Google would have happily informed you. Its root word, not its synonym, is "aggression". Microaggressions are by definition not intended to hurt, or they would be, you know, aggressions.
That's an important concept, because it augments your theory of mind with this fact: There are things that you do, from time to time, that hurt other people in ways too small for them to complain about. For the most part, these things are random and not worth the effort to try to predict and avoid. And no one would ever call out one of these things as offensive, because taken individually, they aren't.
But certain individuals, and certain groups of people, are "randomly" subject to that sort of thing far more often than others. Your barely-hurtful word is a barely-wet raindrop in the ocean of hurt that defines their world. And certainly you can't do anything about their ocean, but maybe, sometimes, it could be worth your effort to not participate.
Basically, I'm not trying to give you rules to follow. I'm trying to suggest that the world does have patterns, and the way to relate to patterns is with rules. So please, make your own rules, but don't reject the whole idea-- or else live in a world you understand and fit in to a little bit less.
I will reiterate, though, that it's impossible to capture or represent the feelings of a large group with a one-sized-fits-all rule. Whether I accept them or reject them depends exclusively on the reality of the situation and audience.
Great, and now you've edited so that I look like the crazy one...
> harmless and without ill intent
ag·gres·sion əˈɡreSHən/ noun hostile or violent behavior or attitudes toward another; readiness to attack or confront.
Aggression is, by default, defined by intent, not perception.
> You're a well-meaning person, and you want to avoid causing unnecessary harm with your words. So when you're around people who have really different life experiences than you, how do you make sure you don't cause harm without meaning to?
This was my point about there existing no universal set of social rules. So when someone says "don't say X, it's offensive," I have a tendency to look at that as more a matter of latter-day Tumblr cause celebre than anything real.
As a matter of brutal honesty, when someone tells me that X is offensive to them, I respond by not doing X anymore. I don't accept wide swath rules about such things and apply them universally, unless I observe them with any frequency in the wild. If we all cast that net, communication would be extraordinarily difficult and language impossibly rigid and uninteresting.